Please allow me to clarify what I meant.
The young INFPs I have known bore an air of tragedy because their Fi always compared the moral purity of our society (America) with their own and found it wanting. Pair their resulting disappointment with ineffective mobilizing because their Ne ran wild without Si's (or Te's) consistency and reality-checking to back it up. All of them admitted in various ways that they felt backed into a hole, that our world would never be up to their expectations.
In comparison, INFJs' hallmark is to improve the human condition via social dynamics (Ni-Fe). To bring about a more beautiful world for everyone, sometimes without their consent [think Hitler]. The young INFJs I have known (self included, for a time) can become so enthralled with the possibility of their better world that they too lose touch with reality or find it too distasteful to touch and thus retreat from it, literally chasing after the beauty in their heads.
(I admit that articulating my concept of What It Means To Be INFP is difficult and some aspects of their functions elude me. Accordingly, this comparison may come off as depicting INFJs in a better light than INFPs, but this is not intended. We all have our demons and none of them are pretty. I figured links would be a better option than a point-by-point analysis that could derail the thread.)
Again, these observations are based on young, barely developed types. INFPs and INFJs are much more complex than this, shown with three nifty links. I admitted it is impossible to contrast the types within two lines and purposefully inserted a disclaimer -- "broad strokes cover the cracks". Many of my posts on this forum attempt to make it clear that every type has many variations, and that relying on superficial descriptions for understanding them is a disservice to the seeker's understanding and the complexity of typology itself.